I have a client that has a Windows Server 2012 R2 Standard running FileMaker Server 15 on a virtual server in the Amazon cloud. Most of the company uses VPN connections to connect to it using FMP clients and all works well. However, the admin sometimes wants to do some maintenance work on FileMaker Pro or FileMaker Pro Advanced from the same server machine. This is not regularly used, but it has stopped working. Both FMP and FMPA are on this server and both are at version 15.0.3. Whenever they connect to the service on the same machine, they can connect for a short while and then receive a disconnect. So the startup script runs and at different points on the script (not the same place), they receive a disconnect from the server with the option to reconnect (which never works). I've tried connecting using the domain name, LocalHost, 127.0.0.1, as well as its LAN IP. The domain name does have SSL on it. These all behave as expected such as not using the domain name gives the SSL warning. They all get in and start the script running and then get a disconnect. It happens on both FMP and FMPA. They have Cybereason and Symantec Cloud antivirus and Amazon Center Stage as part of their Amazon instance. The OS's software firewall is turned off and managed externally by Amazon's VPN and not on the same machine. When it disconnects, the Server log file gets a 36888 ID Error in the Schannel. They also get a 30 ID Warning from "FileMaker Server 15".
Any suggestions would be appreciated or suggestion to try. Thanks for any input.